Components of Interaction (1 of 3)
Consider the graph shown below.
Overall, there is an interaction since the effect of B depends on the level of A. However, only one piece or component of the interaction is present: The effect of B is greater at A3 than it is at A1 or A2. No other part of the interaction is present since the effect of B is the same at A1 as it is at A2.
It is possible to test components of interaction for significance by using the procedures described in the section on specific comparisons among means. The test of whether the effect of B is significantly different at A3 then it is at the other two levels is done with the comparison among means shown on the next page.